I just have a 4 blade fan with an aluminum radiator, no shroud. Have a 302 5 speed. Car never has gotten hot. This summer has been unusually cool here in NE KS this year though. Don't have AC though.

My experience with using flex fans is that they are lousy, at least without a shroud. I have a tight engine compartment in my '78 and I shoved a well built 351W in it. The water pump flange is so close to the factory three row radiator that I don't need a spacer, the fan ended up 1 inch away from it as is. I had nothing but problems with overheating at low speeds when above about 80 degrees ambient. I finally solved the problem by putting a five blade steel factory style fan on it No overheating since and I can idle as long as I want to. My theory is that the flex fan (aluminum Flex-a-lite) blade profile is not aggressive enough to move air when it's installed without a shroud. once it heats up, even moving forward at lower speeds was problematic because the fan flattened out, thus moving less air than it needed to cool.

Mileage suffers a bit because of the additional power required to drive the fan but it's worth it to me. My system hits about 190 degrees when the thermostst opens (it's rated at 180) and the temp drops to about 165-170. So far I'm good up to about 100 degrees ambient temps without overheating when stuck idling for extended periods.

As some here know, I'm not a "fan" of electric fans.  Our 66 has a 5.0, with AOD, AC, seven blade fixed fan on a new clutch hub, 2 core aluminum rad, spring in the lower hose, and a "proper" shroud.  Never runs above the stat (194) even when crawling up Pikes peak or running  across I-80 at 80+.  Both times with the AC on (don't want any of those whinie noises from the  passenger seat area)

So I would recommend you get a clutch hub that works (mine is a new replacement for an 89 Lincoln TC) and holds the fan about 1/2" from the rad.  As for a shroud you can shop the various sources and maybe you can get one that fits right.  Correcct, from what I've read, is about  1" larger opening than the fan dia.  which will leave 1/2 all the way around.  Mine runs about 5/8" to 3/4".   You can probably find something with the proper opening but it may  not center on your fan/rad combo.  Likely a little custom work will be needed. 

Also, you want the  edge of the shroud opening to be at 50% of the fan blade width.  In other words, you should be able to see about half of the  blade when you look straight down on the edge of the shroud.

And also, the rad needs to be sealed against the core support so all the air is pulled through the rad and, of course, the shroud needs to be sealed well against the rad.

If you do a little research, you can probably find various  info on making your own shroud.  Mine only took me four days butt (TS&T) I saved over $100  bux...lol.

No joking though, a number of guys here have made their own so it ain't rocket science.

I believe the fan/shroud is the single most important part of the cooling system.  A marginal rad with no shroud and a four blade fan will not get it.  But a marginal rad with a good fan and a proper shroud will  probably work fine except in the worst conditions.

Finally, take a couple of pieces of 1/16" gas rod and wind a coil around  a large socket.  Stick that in the lower hose.  You may not need it but it is good insurance.

Then...keep driving that 'Stang every day.  You can be our  poster child for driven classic Mustangs.  Love it!!

And, if you can drive it every day, you can prolly drive it to Franklin...right?

BB

Bullet Bob wrote:

So I would recommend you get a clutch hub that works (mine is a new replacement for an 89 Lincoln TC) and holds the fan about 1/2" from the rad.  As for a shroud you can shop the various sources and maybe you can get one that fits right.  Correcct, from what I've read, is about  1" larger opening than the fan dia.  which will leave 1/2 all the way around.  Mine runs about 5/8" to 3/4".   You can probably find something with the proper opening but it may  not center on your fan/rad combo.  Likely a little custom work will be needed. 

Also, you want the  edge of the shroud opening to be at 50% of the fan blade width.  In other words, you should be able to see about half of the  blade when you look straight down on the edge of the shroud.

Finally, take a couple of pieces of 1/16" gas rod and wind a coil around  a large socket.  Stick that in the lower hose.  You may not need it but it is good insurance.

Then...keep driving that 'Stang every day.  You can be our  poster child for driven classic Mustangs.  Love it!!

And, if you can drive it every day, you can prolly drive it to Franklin...right?

BB

I bought my rad new and its only a year old.  its a 3 row rad so that should work good..  I do have a coil in the lower rad hose so I'm set there. 

I have the 15" flex fan sitting in the garage and a spacer in there as well.  not sure how close to the rad it will put the fan.  I'm guessing with in 2 inches to the rad.  Its been a long time since I had it on there.  I was considering buying one of those nylon fans to use in place of the flex fan.  Anyone have any experience with those?

I agree that a fan shroud is a must with a fan.

I have no doubts my car will make it to the Franklin (the bash right???).  Its not a pretty mustang by any means but its a daily driver.  I'll mention the bash to the wife and see what she thinks.
 

Rudi wrote:

I had 180 temps at all times and never overheated, I was in a parade a while ago with the Zirgo and the engine got up to 210 before I bailed out.

not to argue, but 210 is not hot.  Water doesn't boil till 212, if you have a properly functioning pressure cap and recovery system, you should be able to run water temps up to 250 and not have a problem.
After exploding my past flex fan, I drove my car for a whole without a fan.  In 100 degree temps in SoCal stop and go traffic, the car got to 220 a couple of times but it wasn't an issue.  Obviously I didn't leave my car idling in the parking lot.

My brother now owns my old XJ jeep.  He recently took the fan and motor controller out of a Volvo (it's the same fan motor as the Taraus but with a bolt on shroud) at a pick a part, and installed it.  It gets two miles per gallon better on the freeway than with the fan clutch, is much quieter, and actually cools better when he's out crawling.

Fan selection is really important, and most of the aftermarket ones are garbage.  The Spal stuff is okay, and the "adapted" OE stuff is best, IMO.
 

Living Yuma az and having temp in the 120 range I know soming about hot. I have a 88 suburban that I put a mark VII fan in. That big fan fits in the OE fan shroud and with the AC on never gets hot even in traffic. I'm a fan of electric but I do agree that the aftermarket stuff doesnt work properly. fitting a OE fan is the best option. Just my 2 cents worth.  

I went to a two-row aluminum 20" with auto cooling from Virgina Classic ($230 at the time and same I had paid for the copper a year earlier).  Same unit MS used to sell and it works excellent.  I had a 20" three row copper but had some heating issues.  Changed a number of things along with the rad but been happy  ever since.

I think they also  make that in a 17" stock replacement, but...going to the 20" is  duck soup simple and by going to the 20" al from a 17" copper you will nearly double your rad capacity.

BB

Last edited by Bullet Bob (9/03/2013 9:36 PM)

thanks for the tips guys

I think I'm going to nurse the rad for a while and look for a aluminum 3 row that will fit the stock location and add a fan schroud.  Things have been going good since I put the fan back on other than the sucky small seeping leak. 

Question, the schrouds that NPD has that extend about 3 inches will they work with my flex fan?

I've also looked at the generic schroud from summit but it looks more like a sheild to keep your hand out of the fan blade than actually add in cooling.

http://www.summitracing.com/parts/spe-4348/overview/

I've been looking at this one from NPD.  I think it will add in cooling as well as keeping me from cutting my fingers off.  hehe.

http://www.cjponyparts.com/scott-drake-fan-shroud-plastic-3-1-2in-wide-260-289-1965-1966/p/FANS11/

I think that with a 3 row aluminum rad will work fine to keep the temps cool.


Yes I have the spring in the lower hose.  Running a 17" blue 5 blade flex fan.  current rad is a leaking 3 row copper rad.

Thoughts?

FWIW, I'm using an aluminum Summit racing (stamped Northern on top) and a repop shroud with a 17" flex fan and I'm having no cooling issues at all.

http://www.cjponyparts.com/engine-fan-shroud-260-and-289-1964-1966/p/FANS1/

(edit) yes, I know the fan could be a half inch or so closer to the radiator but it works fine so I'm not bothering. I once put a fan into a radiator when I scraped headers and it tilted the engine up :-o

Last edited by Jeff in GA (9/04/2013 6:34 PM)